A conventional ink jet recording apparatus as a liquid ejection apparatus includes a carriage, a recording head loaded on the carriage, and an ink cartridge as a liquid cartridge for storing ink to be supplied to the recording head. In the ink jet recording apparatus, printing is performed for a recording medium by ejecting ink from a nozzle provided at the recording head while relatively moving the carriage and the recording medium.
Ink jet recording apparatuses include a so-called off carriage type which is the type without an ink cartridge loaded on a carriage in order to reduce load on the carriage and to make the apparatus compact and thin. In the off carriage type ink jet recording apparatus, the ink cartridge usually includes an ink pack for housing ink and a case for housing the ink pack. The ink inside the ink pack is supplied to the recording head by supplying air pressurized by a pressure pump into a space between the ink pack and the case and crushing the ink pack, or by gravity by locating the ink cartridge above the carriage.
In the off carriage type ink jet recording apparatus, the ink cartridge is detachably attached to a cartridge holder provided at the recording apparatus. When the ink in the ink pack is used up, the old ink cartridge is removed from the cartridge holder, and a new ink cartridge is attached to the cartridge holder.
There are proposed various ink jet recording apparatuses which are improved to attach and detach the ink cartridge easily to and from the cartridge holder. For example, the ink jet recording apparatus disclosed in Japanese Laid-Open Patent Publication No. 2002-200749 includes a cover member which is opened when the ink cartridge is operated to be attached and detached, and an operation lever rotatably provided inside the cover member. The ink cartridge is attached and detached to and from the cartridge holder by rotating the operation lever.
In the recording apparatus disclosed in Japanese Laid-Open Patent Publication No. 2002-200749, fixation of the ink cartridge to the cartridge holder is mainly performed by means of the cover member. However, in the state in which the ink cartridge is attached to the cartridge holder, a gap occurs between the cover member and the ink cartridge. Therefore, the ink cartridge swings in the cartridge holder due to vibrations and drop during transportation and printing. As a result, there arises fear that an ink lead-in tube of the ink pack and an ink lead-out portion of the cartridge holder will become disconnected and an air lead-out tube of the ink cartridge and an air lead-in portion of the cartridge holder will become disconnected. Incomplete connection between the ink lead-in tube and the ink lead-out portion causes leakage of the ink, and incomplete connection between the air lead-out tube and the air lead-in portion makes it difficult to supply the pressurized air to the ink cartridge with high accuracy.
Therefore, in order to suppress swing of the ink cartridge in the cartridge holder, the cartridge holder and the ink cartridge are respectively provided with projections for positioning which are engaged with each other. However, when the ink cartridge is removed from the cartridge holder, it is not necessarily easy for users unaccustomed to replacement of the ink cartridges to pull the ink cartridge with strong force to release engagement of the projections.